The present invention relates to absorbent articles such as sanitary napkins, panty liners, incontinence pads, and the like. More particularly, the present invention relates to a highly efficient absorbent article for use with a supporting garment, such as a menstrual pant (or panty).
Absorbent articles such as sanitary napkins, pantiliners, and incontinence pads are devices that are typically worn in the crotch region of an undergarment. These devices are designed to absorb and retain liquid and other discharges from the human body and to prevent body and clothing soiling. Sanitary napkins are a type of absorbent article worn by women in a pair of panties that is normally positioned between the wearer""s legs, adjacent to the perineum. Sanitary napkins of a wide variety of shapes and dimensions are currently used by women for the collection of menses and other bodily discharges.
In the past, a number of efforts have been directed at providing sanitary napkins that maintain contact with the wearer""s body. One attempt to provide such body contact is disclosed in U.S. Pat. No. 2,747,575 issued May 29, 1956 to Mercer. The Mercer patent discloses a catamenial bandage having a longitudinal hump which bulges towards and may contact the body of the wearer. The catamenial bandage described in the Mercer patent suffers from several disadvantages, however. For instance, the size and shape of the absorbent pad and hump in the Mercer bandage appear to limit the conditions under which the bandage is able to maintain contact with (and conform to) the body of the wearer.
U.S. Pat. No. 4,425,130 issued to DesMarais on Jan. 10, 1984, discloses a compound sanitary napkin that comprises a primary menstrual pad and a panty protector joined to one another at their corresponding ends in such a manner that the two constituents are free to move relative to one another along essentially their entire common length. The primary menstrual pad is intended to absorb the bulk of the bodily fluids discharged by the user, while the panty protector is intended to protect the user""s garments from soiling. In use, the relative freedom of movement between the primary menstrual pad and the panty protector serves to maintain the primary menstrual pad adjacent the user""s crotch region while the panty protector remains associated with the user""s undergarment.
It is also desirable that sanitary napkins, not only maintain contact with, but conform as closely as possible to the wearer""s body. Such a body-conforming capability increases the effectiveness of the sanitary napkin by reducing the possibility that menses will travel around the perimeter of the sanitary napkin and leak. There have been a number of recent efforts to provide sanitary napkins and other absorbent articles with improved body-conforming characteristics. For example, U.S. Pat. No. 4,950,264 issued to Osborn on Aug. 21, 1990, is directed to a thin, flexible sanitary napkin that is capable of handling medium to high menstrual flows. The sanitary napkin in the Osborn patent is described as being highly flexible and conforming very well to the various shapes of the female urogenital region. The Osborn patent discloses a sanitary napkin having a flexure resistance of less than about 130 grams; a test capacity of at least about 8 grams (per a 66.5 square centimeter section); and a total capacity of at least about 20 grams. The sanitary napkin may have a caliper of 2 mm, or less. The Osborn sanitary napkin is described as being worn in the wearer""s underwear, and is preferably scaled to the width of the crotch of the wearer""s underwear.
In addition, PCT International Patent Application Publication No. WO 94/16658, entitled xe2x80x9cGenerally Thin, Flexible Sanitary Napkin With Central Absorbent Humpxe2x80x9d, published in the name of Osborn on Aug. 4, 1994, discloses a generally thin, flexible sanitary napkin which has a central absorbent hump, and is capable of handling medium to high menstrual flows. The hump is particularly useful in fitting into the space between the wearer""s labia to more readily intercept menses and other bodily discharges when they leave the wearer""s body. The search, however, has continued for improved sanitary napkins, particularly sanitary napkins that will achieve even better fit.
For example, current sanitary napkins are typically worn in a loose-fitting undergarment. Such sanitary napkins are necessarily designed to be large enough so that in the event of any shifting of the sanitary napkins from their position under the vaginal introitus, they will still be able to intercept the wearer""s bodily discharges. Thus, a need exists for an absorbent article that fits closely, and comfortably against the wearer""s body which is not required to be designed to compensate for poorly-fitting undergarments.
It has been theorized by the inventors that if an absorbent article with sufficiently high capacity is held closely but comfortably against the wearer""s pudendal region, and in particular, covers the vaginal introitus, the surfaces of the labia majora, and perineum, during the entire period throughout which the absorbent article is worn, then an absorbent article can be provided which is of a greatly reduced size in comparison to current sanitary napkins. Such an absorbent article need only be large enough to cover these regions of the wearer""s body, rather than being sized to accommodate shifting of the product with respect to the introitus.
The present invention is directed to highly efficient absorbent articles for wearing by a human female such as sanitary napkins, panty liners, and adult incontinence pads (xe2x80x9cabsorbent padsxe2x80x9d) for use with a specially designed supporting garment (or undergarment), such as a menstrual pant (or panty).
The absorbent article of the present invention preferably maintains contact with and covers the inside surfaces of the wearer""s labia, the exterior surfaces of the wearer""s labia, and covers the menstrual panty. Coverage of all three of these surfaces provides the absorbent article with the greatest opportunity to provide superior leakage protection and to maintain the wearer""s body in a clean condition, free of menses. The absorbent article is preferably worn with a menstrual panty that comfortably fits against and conforms to the inside and outside surfaces of the wearer""s labia majora. This conforming fit is present regardless of whether the wearer""s legs are apart, or together. The menstrual panty preferably maintains a modified cusp-shaped cross-sectional configuration in this area throughout a range of body motions. The absorbent article preferably does not alter or override the tendency of the menstrual panty to achieve this fit. The absorbent article preferably flexes under the forces exerted by the menstrual panty so that it assumes a similar (and preferably the same modified cusp shape) in this region as the menstrual panty.
The absorbent article and menstrual panty preferably function in a manner that can be thought of as being analogous to covering a cut with a bandage. Body fluids are captured at or near their source by using close body contact and comfortable forces to hold the absorbent article in place at the source of bodily fluids. This can be contrasted with using overly-sized sanitary napkin in a loose-fitting pair of panties, which function in a manner that can be analogized to the use of a drop cloth beneath the source of bodily fluids. The absorbent article is preferably sufficiently small that it only covers the wearer""s pudendal region and immediately adjacent regions, and in particular, covers the vaginal introitus and the surfaces of the labia majora. The absorbent article may also cover the wearer""s perineum. The absorbent article preferably does not extend forward beyond the wearer""s mons pubis. The absorbent article preferably does not extend rearward to contact the wearer""s anus to avoid sensitive nerve endings therein. This provides a more comfortable, and less noticeable absorbent article since it occludes less of the crotch region of the wearer""s body and allows air to circulate around the same. The absorbent article preferably cups the labia from front to back.
The absorbent article also preferably does not cover areas of the wearer""s body that undergo substantially degrees of movement (that is, the absorbent article will only be placed adjacent to xe2x80x9clow motion zonesxe2x80x9d of the wearer""s body). In particular, it is desirable that the edges of the absorbent article will not be contacted by the inside surfaces of the wearer""s thighs when the wearer walks, or otherwise moves about. This overcomes a drawback of conventionally-sized sanitary napkins and pantiliners, which being comparatively stiff relative to the absorbent article of the present invention, will transfer forces applied to the edges thereof to other portions of the sanitary napkin or pantiliner, causing the same to bend or crumple, and/or shift from the desired position under the wearer""s vaginal introitus.
In several embodiments, the absorbent article of the present invention comprises a liquid pervious topsheet, a liquid resistant, or liquid impervious backsheet joined to the topsheet, and an absorbent core positioned between the topsheet and the backsheet. In one embodiment, the absorbent article has a cup-shaped configuration. In other embodiments, the absorbent article can be generally flat prior to use. The absorbent article, as discussed above, is substantially smaller than conventional sanitary napkins. For example, if cup-shaped, the absorbent article may have an overall length when measured in its curved configuration of less than or equal to about 6 or 7 inches (about 15 cm to about 18 cm), or even less than or equal to about 5 inches (about 12.7 cm), and a width of less than or equal to about 3 inches (about 7.6 cm). In one preferred embodiment the absorbent article measures about 6 inches (about 15 cm) by about 3 inches (about 7.6 cm). The absorbent article of the present invention preferably has a surface area measured in flat condition that can be less than or equal to about any of the following: about 20 in2 (about 130 cm2); about 18 in2 (116 cm2); about 15 in2 (about 97 cm2 (or 100 cm2)); about 12.5 in2 (about 80 cm2); or about 10 in2 (about 65 cm2).
The absorbent article is preferably highly flexible, and preferably has a flexure resistance of less than or equal to about 100 grams, more preferably less than or equal to about 70 grams, and most preferably between about 30 and about 50 grams. The absorbent article preferably has a total capacity of greater than or equal to about 20 grams of liquid, more preferably greater than or equal to about 25 grams of liquid. The absorbent article preferably has a ratio of total capacity to surface area of greater than or equal to about 2 g/in2 (about 0.3 g/cm2), more preferably greater than or equal to about 2.5 (g/in2) (about 0.4 g/cm2).
In one particularly preferred embodiment, the topsheet of the absorbent article comprises a high loft fibrous material. The absorbent article with the high loft fibrous material is preferably comprised of fine polymeric fibers that provide a plurality of filamentary members for contacting the wearer""s body. The high loft fibrous topsheet material serves several functions. It allows the absorbent article to achieve a xe2x80x9cmacroxe2x80x9d fit that is capable of fitting virtually all women, and a xe2x80x9cmicroxe2x80x9d fit that adjusts to the particular body contours of individual women. The high loft topsheet also tends to break the flow of menses along the wearer""s body, and intercepts menses flowing along the wearer""s body, and allows such bodily exudates to be acquired into the absorbent core. The absorbent core can comprise a variety of different high efficiency absorbent cores. In one preferred embodiment, the absorbent core comprises a highly porous HIPE polymeric foam that is preferably either slit, in the form of strands, particles, or a plurality of upright, spaced apart columns. The term xe2x80x9cHIPE polymeric foamsxe2x80x9d refers to hydrophilic, flexible open-celled foam structures which are preferably prepared by polymerizing high internal phase (HIPE) water-in-oil emulsions. The backsheet can comprise a conventional liquid impervious film, or a breathable material.
The absorbent article may be provided with other optional features. In some embodiments, the absorbent article may be provided with elastics, preferably in the form of an elastomeric film/nonwoven laminate along the longitudinal edges thereof for forming the absorbent article in a cup-shaped configuration, in a manner that is comfortable for the wearer. The absorbent article may have a fastener for fastening the absorbent article to the specially designed supporting garment. In a preferred embodiment, the absorbent article has a plurality of fine hair-like projections on the garment-facing surface thereof which engage with and adhere to a specially designed knit supporting garment. In other embodiments, the absorbent article may be provided with a raised portion on its body-facing side. In such a case, the absorbent article may have an absorbent tube on its body-facing side so that it is in the form of a xe2x80x9ccompoundxe2x80x9d absorbent article.